Automatic fan damper



Feb. 13, 1951 c. PRUDHON 2,541,665

AUTOMATIC FAN DAMPER Filed June 17, 1948- INVENTOR. CLARK P/e UDHO/V ATTORN Y Patented Feb. 13, 1951 2,541,665 AUTOMATIC FAN DAMPER Clark Prudhon, Fort Atkinson, Wis., assignor to James Manufacturing Company, Fort Atkinson, Wis., a company of Wisconsin Application June 17, 1948, Serial No. 33,494

2 Claims.

The present invention relates to an electric fan with a housing having two semi-circular damper blades at the outlet which are opened by the blast of air from the fan and closed by gravity and used generally for moving air into or out of a building or room through an opening in the wall, around which the device is mounted.

Objects of the present invention are to provide pivot rods which are suitably secured to the inner edges of the damper blades, the bottom rods being formed by bending them forwardly and then downwardly a distance forward from the first bends and slidably extending the ends through openings in' the lower bracket, the ends being preferably cone shaped and adapted to rest on the bracket and act as a support for the dampers, the upper and lower pivots being closely spaced transversely whereby when the blades are closed their adjacent edges are in juxtaposition.

Another object of the present invention is to provide and mount the two damper blades which when open, will provide a free flow passageway for the discharged air.

A further object of the present invention is to cut away portions at the corners of the damper blades in order to provide room for the pivot support brackets and having means whereby when the dampers are fully opened, one of the pivot supports will act as a stop for the blades.

Generally stated objects of the present inven tion are to provide a device of the character which is simple, easily manufactured at low cost, efiicient and pleasing in appearance.

To these and other useful ends my invention consists of parts, combinations of parts or their equivalents and mode of operation as hereinafter described and claimed and shown in the accompanying drawings in which:

Fig. 1 is a side elevational view of my improved device with the housing and fan blade brackets sectioned on lines l-l of Figure 3, showing one of the damper blades closed.

Fig. 2 is a view similar to Figure 1 showing one of the damper blades open.

Fig. 3 is a front elevational view of a fraction of my improved device with the dampers in a closed position.

Fig. 4 is a front elevational fractional view of my improved device with the blades open.

As thus illustrated the motor of my improved device is designated in its entirety by reference character A, the fan blade assembly is designated in its entirety by reference character B. The housing in its entirety is designated by reference character 0.

2 The housing of my device is shaped preferably as illustrated in the figures, the rear flanges It of which are adapted to be easily secured to the wall of the room or building by means of suitable screws or bolts, the flange having holes therein for this purpose. The circular part of the housing is designated by reference numeral 1 I and the portion between members l0 and H is desi nated by reference numeral l2 thus forming a shape which is pleasing in appearance and providing a flared inlet as at i3 which improves the efficiency of the fan. Motor A is supported on flange ill by means of suitable supporting members M and I5, member B being mounted on the front end of motorshaft l6 and is positioned within housing member I l and near the rear edge thereof. The front edge of member H has a narrow outwardly turned flange H for holding this edge in a true circle.

Thus it will be seen by scrutinizing the figures that there is provided a large and easy path for the air as it approaches therear end of member 1!; that member ll may be made in a suitable diameter conducive to efficiency and appearance and that the front end of member I l with flange Ii forms a suitable means for supporting the damper blade brackets and for providing a suitable surface against which the blades rest when closed.

I secure a bracket 29 to the inside surface on the upper side of member I I and another bracket 2| to the inside surface at the. bottom of member I I. Members 26 and 2| are transversely centrally and vertically positioned. I provide two semicircular damper blades 22 and 23 which are made from flat stock having a diameter when closed which registers with the outer diameter of flange ll. When these dampers are closed, their adjacent edges are in juxtaposition as clearly illustrated in Figure 3. The inner edges of members 22 and 23 are rolled into a circle as at 24 and 25 so as to embrace rods ZS-26 at their tops and the upturned portion of rods 2'l2'|. Rods 26 slidably extend through suitably positioned openings in member 28. Members 22 and 23 are cut away at their upper corners as at 28 and '29 so the damper blades will not touch member 20 except when they are wide open as shown in Figure 4.

It will be noted by observing Figure 3 that rods 26 are free to move vertically in member 20, the vertical position of members 22 and 23 being determined as follows:

- The lower corners of members 22 and 23 are cut away as at 30 and. 3| so these members will not contact member 2] when the damper blades are closed as shown in Figure 3. Lower rods 21 are turned outward as at 35 (see Figures 1 and 4), the outer ends are turned downward as at 36. These outer ends slidably extend through closely spaced holes in member 2|. Member 2| at its outer end is bent downwardly and rearwardly as at 31 and 38. The lower ends of members 21 are pointed as at 39, the points being positioned so the damper blades will be held in the positions shown when closed or opened. Thus the dampers are supported on these points so very little resistance will be offered to the turning movement of the damper blades.

It will be noted that points 39 are a distance forward of the vertical plane of rods 26. Thus this position represents the amount of gravity relative to the weight of members 22 and 23 which will act to close the damper blades and hold them closed as illustrated in Figures 1 and 3 until motor A is started. In other words if a straight line is drawn between points 39 and rods 26 the angle of this line represents the axis on which the damper blades turn.

By observing Figure 4 it will be seen that the damper blades will tend to close by gravity; that they will be stopped by member 26 when in the position shown in Figure 4; that because of points 39 there never will be enough friction against the movement of the damper blades to prevent their sensitive operation; that when the dampers are closed there are practically no openings for the passage of air; that curved portions 24 and 25 are on the outer side of the damper blades so the blades will lie flat on flange I! when the blades are closed. Thus it will be seen that applicants automatic fan damper meets all of the requirements recited in the preamble of this specification.

Having thus shown and described my invention, I claim:

1. A fan and an automatic damper therefor comprising in combination, a housing having a fan therein and means for driving the fan to force air forwardly therethrough, forwardly extending upper and lower brackets secured to opposite sides of the outlet end of the housing and being positioned in vertical alignment, two semicircular damper blades adapted to close the outlet end of the housing when the fanis not operating, the upper corner of said damper blades having upwardly extending rods secured thereto, openings in said upper bracket adjacent the forward end of the housing adapted to slidably and rotatably engage the rods, the lower corners of said damper blades having secured thereto other rods which extend forwardly a distance when the damper blades are in a closed position and then downwardly a distance from the damper blades, said lower bracket having openings a distance from the front end of the housing through which said downwardly extending ends of the other rods rotatably and slidably extend, a stop bracket positioned below the openings in said lower bracket, the downwardly extending ends of said last rods being cone shaped and adapted to rest on said stop bracket, whereby when the fan is operating, the blast of air from the fan will act to counteract gravity and cause the damper blades to open the outlet end of said housing for free passage of air therethrough.

2. A fan and an automatic damper therefore comprising in combination, a housing having a fan therein and means for driving the fan to force air forwardly therethrough, forwardly extending upper and lower bracket secured to opposite sides of the outlet ends of said housing and being positioned in vertical alignment, two semi-circular damper blades adapted to close the outlet end of said housing when the fan is not operating, the upper corners of the damper blades having upwardly extending rods secured thereto, openings in said upper bracket adjacent the forward end of the housing adapted to rotatably engage the rods, the lower corners of said damper blades having secured thereto other rods which extend forward a distance when the damper blades are in a closed position and then down wardly a distance forward of the damper blades, said lower bracket having openings a distance forward from the front end of the housing through which the downwardly extending ends of the other rods rotatably and slidably extend, means adapted to form a free support for said damper blades, whereby when the fan is operating, the blast of air from the fan will act to counteract gravity and cause the damper blades to open the outlet end of the housing for free passage of air therethrough.

CLARK PRUDHON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,187,490 Taylor June 13, 1916 1,189,572 Ilg July 4, 1916 1,251,593 Truitt et al Jan. 1, 1918 FOREIGN PATENTS Number Country Date 130,232 Switzerland Mar. 24, 19 17 

